Warper tension device



Feb. 21, 1956 M, L. ROBINETTE ETAL 2,735,632

WARPER TENSION DEVICE Filed March 25, 1953 m mJ 4 M d? 2 -10, 2/, Gm--- 2 EH .9? B H 3 a 7 L L F102 3 3 L. ROB/NE 7' TE WE/VDELL G FAW MARIO/V I INVENTOR. wu .9.

g ii ATTORNEYS nite States WARPER TENSION DEVICE Application March 25, 1953, Serial No. 344,637

4 (Ilaims. (Cl. 242-150) The present invention relates to a yarn tension device, and more particularly to a tension device used in connection with creels in which a large number of separate yarns are drawn from different yarn packages.

In the manufacturing and processing of textile materials there are many points at which it is necessary to control the tension. The method of controlling the tension and the precision with which it must be controlled varies from process to process. There is perhaps no phase of the textile industry which requires more precision control than that concerned with the processing of synthetic yarn. In the processing of acetate yarn, for example, small variations in tension may be extremely objectionable because the high degree of uniformity of the individual strands exaggerates any slight deviation from the normal arrangement of the fibers in a fabric.

In the manufacture of acetate yarn, it is very important that the tension be controlled in the spinning process, in twisting and in unwinding. However, of all the processes encountered, the tension in warping is, perhaps, the most critical. In the preparation of section beams, for example, there may be from 600 to 1000 ends running parallel, each end having a dilferent bobbin or cone as its source.

Any variation in the average tension will affect the density of the beam. If the tension from a set of bobbins should increase progressively as the yarn is withdrawn, the first beam wound from the creel would have a lower density and greater diameter than a later beam wound from the same creeling. Since the yarn from these beams may eventually be combined in the same fabric, there is a possibility that these variations would be detrimental to the quality of the finished product. If the tension should vary from end to end in the warp sheet, there would be a variation in density within the beam which would show up as ridges and valleys on the surface of the beam. Obviously, when this yarn is withdrawn from the beam to be woven, some of the ends will be tighter in the fabric since fewer yards will have been wound in the valleys than on the ridges. This condition, if of sufficiently great magnitude, may cause stretching of the tight ends, and, under any circumstances, it may cause warp streaks. Therefore, it is very important to control the warping tension when processing acetate yarn. This is true whether the warping is carried out by the yarn producer or the weaver.

There are several different types of warp tension devices in use today. The most common one consists of two posts with two discs on each post. The yarn passes between the two discs on each post with all the angularity, 60-90 degrees, being taken up on the front post. These tension devices are required to maintain uniform tension on each end of the yarn without damaging the yarn. The yarn is withdrawn from bobbins or cones through the tension device and wound up on a beam as one sheet of yarn made up of several hundred ends. It is evident that a uniform tension must be maintained on each end in order to wind up a smooth, dense beam. Any irregularity atent intension will create ridges and valleys in the beam. These warper tension devices must maintain the desired tension to wind a dense beam without doing any damage to the yarn that would aifect the quality of the finished fabric. They are also required to give proper tension to various deniers and twist yarns by using different weight discs to give the desired tension.

One of the most critical yarns is spun twist yarn which contains 0.3 turn per inch twist. With prior tension devices, it is very diflicult to warp this yarn without throwing filament loops in the strand of yarn. In order to warp this yarn without damaging it, the very lightest disc has to be used on the tension device. When using the light disc, the tension was found to be on the low side of the tension range, and the tension was not high enough to prevent the stop motion from kicking the machine off. When running heavier denier and high twist, the yarn tends to kick out of the back disc because there is no angularity taken around the post.

The present invention overcomes this difiiculty in prior structures. According to the present invention, the yarn path takes a total of 60 degrees angularity. To secure this result, three stationary posts are provided, and each post has loosely mounted thereon a pair of tension discs between which the yarn passes. The posts are arranged in a staggered or nonaligned relation so that the yarn takes 20 degrees angularity around each of the three posts, or 60 degrees in all. This 20 degrees is close to minimum angularity for warping of heavy denier or high twist. The three pairs of discs make is possible to add more tension without damaging the yarn. This is made possible by using a lighter disc on the first post, a heavier disc on the second post, and a still heavier disc on the third post.

The invention has as its principal object the provision of a new and improved yarn tensioning device.

Another object of the invention is the provision of a yarn tensioning device in which the yarn path is deflected or adjusted in equal angular steps.

A further object of the invention is the provision of a tensioning device in which the tension is applied progressively and additively while the yarn is passing in a planar relation through the tensioning device.

Still another object of the invention is the provision of a yarn tensioning device which improves the quality of both light denier spun swist and heavier denier high twist yarns.

Yet another object of the invention is the provision of a yarn tensioning device of the class described which is simple in structure, comprise few parts of rugged construction, easy and automatic in its operation, and highly effective in use.

To these and other ends the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings:

Fig. 1 is a plan view of the yarn tensioning device or mechanism constructed in accordance with the present invention, showing the relation of the various parts;

Fig. 2 is a side elevation view of the mechanism illustrated in Fig. 1; and

Fig. 3 is a partial sectional view, on a larger scale than Figs. 1 and 2, showing the relation of one of the snubbing posts and the tensioning discs to the supporting base member.

Similar reference numeral throughout the various views indicate the same parts.

The tension mechanism of the present invention is mounted on a bracket or base plate 11, the under surface 12 of which is provided with a depending dovetail mount 13 and a locking fin 14 for mounting and positioning the tensioning device on a suitable support, not shown. As the dovetail mount and the location fin are of well known construction and form no part of the present invention, further details thereof are not illustrated or described. Sufiice it to say that the dovetail mount serves to hold the bracket 11 rigidly in a horizontal position. The upper surface 15 of the bracket 11 has extended upwardly there from, in parallel relation, three stationary snubbing posts 16, 17 and 18. The yarn 19 is drawn from a cone or bobbin, not shown, and passes through a glass eyelet or thread guide positioned on the right end of the bracket 11, as viewed in Figs; 1 and 2. The three posts 16, 17 and 18 are arranged in a staggered or nonaligned relation so that as the yarn 19 passes over each post, it has imparted thereto a change in its path of 20 degrees. A second small take-01f yarn or thread guide is positioned beyond or to the left of the last post 18, and is offset laterally or out of alignment with the yarn path between two adjacent posts 17 and 18, and cooperates with posts 17 and 18 to impart a 20 bend around post 18, as clearly shown in Fig. 1. Therefore, in passing over the three posts, the yarn path is deflected a total of 60 degrees, as is deemed apparent from an inspection of Fig. l, the advantages of which have been pointed out above. The lower end 21 of each post 16, 17 and 13, may be secured or anchored to the bracket 11 in any suitable manner. For example, the end 21 may be threaded as shown at 22, and secured in a correspondingly threaded opening 23 in the bracket 11, as best shown in Fig. 3. To afford the desired support for the posts, the bracket 11 is formed with depending bosses 24 positioned on the under surface 12 of the bracket in alignment with the posts 16, 17 and 18, as illustrated in Figs. 2 and 3. The lead-in eyelet 20, like guide 25, also is out of alignment with the two adja cent posts, namely posts 16 and 17, and cooperates with these two posts to impart a 20 bend around post 16. It has been found in actual production that with the arrangement illustrated in Fig. l, the angle of approach of the yarn to the eyelet 20 may be or 4 from the thread direction shown in Fig. 1. If, however, this variation is found to be too much with certain type yarns, the variation can be reduced to any desired extent merely by increasing the distance between the eyelet 20 and post 16. in other words, the variation may be controlled by moving eyelet 20 to the right and away from post 16, as viewed in Fig. 1. Due to the space limitations, it would not be desirable to lengthen this distance more than three times that shown in Fig. 1. As another alternative the size of the opening in the eyelet 20 could be reduced slightly in diameter. However, it is preferred to use the size of the eyelet indicated as this is a standard item supplied to the trade. Also, with the size of the eyelet shown, with the posts to eyelet distance illustrated-in Fig. l, satisfactory yarn tensions have been provided so that the angle of variation is not detrimental. Thus, the eyelet 26 and guide 25 are positioned relative to the staggered posts 16, 17 and 18, to provide an apparatus in which the yarn is progressively deflected through equal angles and in the same direction to secure the desired yarn tension.

Each post, 16, 17 and 18, has loosely mounted thereon, a lower disc 39 and an upper disc 31 of the shapes best shown in Figs. 2 and 3. These discs serve to add additional tension to the yarn, as later described. The spaces 32 between the discs 39 and 31 are in substantial horizontal alignment with each other and with the eyelet 20, so that the yarn 19 in passing through the tension device moves substantially in a single, horizontal plane, as shown in Fig. 2. As mentioned above, each post 16, 17 and 18 serves to deflect the yarn 19 through an angle of 20 degrees. Such deflection causes some degree of snubbing of the yarn on the posts, and this snubbing imparts a certain degree oftension to the yarn during its passage over the posts. However, in addition to this snubbing tension, it is desirable to provide an additive tension by means of discs 30 and 31, so that the final tension is a combination of snubbing and additive tension. The equation applicable to this type of device is as follows:

where 1: coefficient of friction wr weight (in grams) of the disc on post 16 wz=weight (in grams) of the disc on post 17 w3=weight (in grams) of the disc on post 18 8:2.718

T1=initial tension T2=final tension It can be seen in the above equation that the final tension, caused by snubbing, is a linear function of the initial tension and an exponential function of the coefiicient of friction. However, with the disc tension device, to be later more fully described, the variation of the initial tension is only additive. This is only a very small variation compared to the final tension. For this reason it is necessary to maintain a certain minimum degree of snubbing on each post 16, 17 and 18, in order to keep the yarn 19 between the discs 30 and 31. Past experience has shown that 20 degrees on each post is about the minimum for the wide range of deniers and twist that has to be handled by such tension device. By using minimum snubbing about each post, the final tension variation is held to a minimum.

In order to secure the additive tension, each pair of discs 30 and 31 are of different weight so they will apply varying pressures to the yarn. In the preferred embodiment, the discs 30 and 31 on post 16 are the lightest, discs 30 and 31 on post 17 are heavier, and finally discs 30 and 31 on post 18 are the heaviest. With this arrangement, a gradually increasing additive tension is applied to the yarn by the discs. For example, the tensioning set up for a 75 denier 0.3 turn per inch is as follows:

Discs on post 1610 grain top and bottom disc Discs on post 1719 grain top and bottom disc Discs on post 18-40 grain top and bottom disc This set-up gives 6 grams final tension Without damaging the yarn, which is on the high side of the desired tension range for good quality beam. Obviously instead of having the discs 30 and 31 on three posts of different sizes and/or weight, the discs on all posts may be the same size and/ or weight, and then additive weights, not shown, of different amounts may be applied to the upper discs 31 of each pair to secure the desired weight differential.

Thus, in addition to the tension applied by snubbing the yarn about the posts 16, 17 and 18, the different weighted discs serve to apply an increasingly additive tension to the yarn along the yarn path and in the direction of the yarn movement, as is apparent from an inspection of the drawings. This combination of tensions provides a yarn having the proper degree of tension without causing damage to the yarn, the advantages of which are deemed apparent.

Thus, the present invention provides a new and improved yarn tension mechanism or device, which deflects the yarn path through equal angularity increments to pro vide equal snubbing tensions; and, in addition, imparts a progressively increasing additive tension to the yarn as it moves through the tension device. These desirable results are secured with a mechanism which is simple in structure, comprises few parts of rugged construction, easy and automatic in its operation, and highly eifective in use.

While one embodiment of the invention has been disclosed, it is to be understood that the inventive idea may becarriedout in anumberof ways. This application is,

therefore, not to be limited to the precise details described, but is intended to cover all variations and modifications thereof falling within the scope of the appended claims.

What we claim and desire to secure by Letters Patent of the United States is:

1. In a yarn tensioning mechanism, the combination with a base, of a plurality of yarn snubbing posts carried by said base, a yarn lead-in guide positioned ahead of said posts for directing the yarn to be the first of said posts, an intermediate post positioned beyond said first post and ofiset laterally from the yarn path between said guide and said first post to cause said yarn to be deflected in one direction and through an angle in passing over said first post, and another post positioned beyond said intermediate post and offset laterally from the yarn path between said first and intermediate posts to cause the yarn to be deflected further in said one direction and through an angle equal to said first angle, said other post being positioned between said intermediate post and a yarn guide and offset relative thereto to cause the yarn in passing over said other post to be deflected still further in said one direction and through said angle.

2. In a yarn tensioning mechanism, the combination with a base, of three yarn snubbing posts extending upwardly from said base, a yarn lead-in guide positioned ahead of said posts for directing the yarn to the first of said posts, the second of said post-s being ofiset laterally from the yarn path between said guide and said first post to cause the yarn in passing over said first post to be deflected in one direction and through an angle to said path, and the third of said posts being offset laterally from the yarn path between said first and second posts to cause the yarn in passing over said second post to be deflected further in said one direction and through an angle equal to said first angle, said third post being positioned between said second post and at take-ofi guide and offset laterally relative thereto so as to cause the yarn in passing over said third post to be deflected still further in said one direction and through an angle equal to said other angles.

3. In a yarn tensioning mechanism, the combination with a base, of three yarn tensioning posts carried by and extending upwardly from said base and around which said yarn passes successively to apply tension to the yarn, a yarn lead-in guide positioned ahead of said posts to direct the yarn to the first of said posts adjacent said guide, the

second of said posts being offset laterally from the yarn path between said guide and said first post to cause the yarn in passing over said first post to be deflected laterally in one direction and through an angle substantially 20 with said yarn path, and the third post being ofiset laterally from said first and second posts to cause the yarn in passing over said second post to be deflected further in said one direction and through an additional 20, said third post being arranged between said second post and a take-oft yarn guide and oiiset laterally relative thereto to cause the yarn in passing over said third post to said takeoff guide to be deflected further in said one direction and through another 20".

4. In a yarn tensioning mechanism, the combination with a base, of three staggered yarn snubbing posts carried by said base and around which said yarn is deflected progressively in the same direction and through three equal angles, a lead-in yarn guide carried by said base and positioned ahead of the first of said posts and in staggered relation with the first and second posts and cooperating with the latter to cause the yarn in passing over said first post to be deflected in said direction and through the first of said angles, and said third post being arranged out of alignment with said first and second posts in said direction to cause the yarn in passing over said second post to be deflected further in said direction and through the second of said angles, said third post being positioned between said second post and a fixed take-ofi? guide, the latter being olfset from said third post in said direction to cause the yarn in passing over said third post to be further deflected through the third of said angles and in said direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,880,810 Clinton Oct. 4, 1932 1,985,665 Munson Dec. 25, 1934 2,185,890 Friday Jan. 2, 1940 2,581,142 Rea Jan. 1, 1952 2,587,114 Chapman Feb. 26, 1952 FOREIGN PATENTS 330,117 Great Britain June 5, 1930 586,865 Germany Oct. 26, 1933 

1. IN A YARN TENSIONING MECHANISM, THE COMBINATION WITH A BASE, OF A PLURALITY OF YARN SNUBBING POSTS CARRIED BY SAID BASE, A YARN LEAD-IN GUIDE POSITIONED AHEAD OF SAID POSTS FOR DIRECTING THE YARN TO BE THE FIRST OF SAID POSTS, AN INTERMEDIATE POST POSITIONED BEYOND SAID FIRST POST AND OFFSET LATERALLY FROM THE YARN PATH BETWEEN SAID GUIDE AND SAID FIRST POST TO CAUSE SAID YARN TO BE DEFLECTED IN ONE DIRECTION AND THROUGH AN ANGLE IN PASING OVER SAID FIRST POST, AND ANOTHER POST POSITIONED BEYOND SAID INTERMEDIATE POST AND OFFSET LATERALLY FROM THE YARN PATH BETWEEN SAID FIRST AND INTERMEDIATE POSTS TO CAUSE THE YARN TO BE DEFLECTED FURTHER IN SAID ONE DIRECTION AND THROUGH AN ANGLE EQUAL TO SAID FIRST ANGLE, SAID OTHER POST BEING POSITIONED BETWEEN SAID INTERMEDIATE POST AND A YARN GUIDE AND OFFSET RELATIVE THERETO TO CAUSE THE YARN IN PASSING OVER SAID OTHER POST TO BE DEFLECTED STILL FURTHER IN SAID ONE DIRECTION AND THROUGH SAID ANGLE. 